Rock drill



Dec. l, 1936. n Y I w- NOBLE 2,062,817

ROCK DRILL im Imlll nu Y Y6 5 'f Ml" INVENToR..

'.l N ,I 1 waffen/Vo@ la BY MZ/l/mu.'

ATTORNEY Patented Dec. l, 1936 UNITED STATES PATENT GFFICE ROCK DRILL Massachusetts Application November 27, 1934, Serial No. 755,010

15 Claims.

This invention relates to rock drills, and more particularly to improvements in vibration reducing means between the drill hammer motor and the drill supporting handle.

An object of this invention is to provide an improved vibration reducing means for the supporting handle of a hammer rock drill of the hand-held type. Another object is to provide improved means for enabling a hand-held rock drill to be easily supported with respect to the work without the transmission of excessive jars and shocks to the drill operator. A further object is to provide an improved yieldable rubber mounting between the drill hammer motor and the drill supporting handle wherein metal-tometal contact between the parts is eliminated,

resulting in a rock drill which may be supported with respect to the work with comparative ease. Still another object is to provide an improved Vibration reducing handle mounting of a comparatively simple, compact design for a hammer rock drill, whereby the overall length of the drill is maintained ata minimum. 'I'hese and other objects and advantages of the invention will, however, hereinafter more fully appear. Y

In' the accompanying drawing, there is shown, for purposes of illustration, one form which the invention may assume in practice.

In this drawing,-

Fig. lis a top plan view of a rock drill equipped with the illustrative form of the improved handle mounting structure.

Fig. 2 is a side elevational view of the rock drill shown in Fig. 1, with parts shown in longitudinal section.

Fig. 3 is a cross sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a perspective view of the rubber torsion sleeve.

Fig. 5 is a perspective view of the split outer metal sleeve.

Fig. 6 is a perspective View of the handle arm element.

Fig. 7 is a perspective View of the inner metal sleeve.

In this illustrative construction there is shown a hammer rock drill of the hand-held type, generally comprising an impact motor I and a supporting handle structure, generally designated 2. The hammer motor herein comprises a cylinder 3 having a bore 4 containing a reciprocatory hammer piston 5. Mounted in a chuck 6, which is carried within a front chuck housing l, i's a drill steel 8 having its shank arranged in position to receive the impact blows of the hammer piston 5. The motor cylinder has a front head 9 interposed between the cylinder and chuck housing, and a rear head I0; and these heads and the chuck housing are secured in assembled relation with respect to the cylinder by means of usual side rods I I, II. As the design of the particular rock drill shown is well known, further description thereof herein is unnecessary, it being evident that the improved vibration reducing means may be embodied in impact tools of various other designs.

Now referring to the improved vibration reducing means between the rear head of the hammer motor and the supporting handle structure, it will be noted that formed integral with the back head I0 of the hammer motor is a lateral boss I2 traversed by a bore I3 oiset a substantial distance from the axial center of the drill and having arranged therein a transverse supporting bolt I4. The ends of this bolt project outwardly in opposite directions from the sides of the drill head I0, and the projections thereof have mounted thereon inner metallic sleeves I5, each having inwardly projecting lugs IB interlocked at I'I with the head I so that these sleeves are held against rotative movement about the `bolt axis with respect to the motor head. Bonded in a suitable manner, as by vulcanizing, permanently to the outer surface of each of the inner metal sleeves I5 is a rubber torsionsleeve I8, rwhile Vthe outer surface of this rubber sleeve is suitably bonded, as by vulcanizing, to a split outer metallic sleeve I9. The elements of the outer sleeve I9 are arranged in a bore 20 formed in the hub 2| of la handle arm element 22, the elements of the outer sleeve I9 being of such curvature thatr they must be sprung inwardly prior to their insertion within the arm bore 2D so that the outer sleeve I9 tightly grips the inner surface of the arm bore. To preclude any tendency of rotative movement of the outer sleeve with respect to the arm hub, the elements ofthe outer sleeve I9 are secured to the arm hub by pins 22a seated in perforations 22h in the arm hub. Projecting from the hub 2l of each handle arm is a lever portion 23 having secured thereto, integrally or in some other rigid manner, a bolt portion 24, and these bolt portions of the handle arms project oppositely from the sides of the drill head and are arranged in axial alinement in a longitudinal plane including the drillaxis and in parallel relation withv the axis of the bolt I4. 'I'hese bolt portions provide threaded ends for receiving nutsv25 for holding in position on the bolts, handle grips 26, 26, preferably in the form of rubber sleeves. It wil thus be seen that when the operator grasps the handle grips 26, 26 of the handle structure and supports the rock drill in drilling position with respect to the work, and the hammer piston of the hammer motor is operated to actuate percussively the drill steel 8, the vibratory action set up within the hammer motor by the hammer piston is substantiallly absorbed by the rubber torsion sleeves I8, these rubber sleeves acting as torsion vibration reducing springs between the lever arms of the handle structure and the back motor head, and arranged in circumferential shear between the handle arm elements and the back motor head.

From the foregoing, it will be seen that rubber in torsional shear is arranged between the supporting parts of the rock drill and the drill hammer motor to reduce the vibrations or jars set up within the hammer motor during the drilling operation, and it will be evident that although but one form of rubber torsion spring structure is disclosed, it may be embodied in various other forms and arrangements to reduce the shocks transmitted by the impact motor to drill supporting means of any character. As the process of bonding the rubber to the metal sleeves is well known to those skilled in the rubber industry, a disclosure of the particular method of attaching the rubber sleeves to the metal parts is herein deemed unnecessary. These and other uses and advantages of the invention will be clearly apparent to those skilled in the art.

While there is in this application specically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration, and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a rock drill, a hammer motor, a supporting means therefor, and vibration reducing means between the hammer motor and said supporting means comprising relatively rotatable parts connected to the hammer motor and said supporting means respectively and rubber in torsional shear bonded between adjacent surfaces of said relatively rotatable parts.

2. In a rock drill, a hammer motor, a supporting handle therefor movable relative thereto and having a supporting lever arm, and vibration reducing means between said hammer motor and said supporting handle comprising relatively rotatable parts, one part connected to the motor and the other to said handle lever arm, and rubber in torsional shear bonded between adjacent surfaces of saidrelatively rotatable parts.

3. In a rock drill, a hammer motor, a supporting handle therefor having handle grips mutually independently movably connected to said hammer motor, and vibration reducing means between said hammer motor and said handle co-mlprising separate shock reducing devices between said hammer motor and said handle grips respectively one shock reducing device individual to each grip and said devices permitting upon yielding thereof said independent movement of said handle grips.

fi. In a rock drill, a hammer motor, a support-l ing handle therefor having handle grips mounted for independent movement, and vibration reducing means between said hammer motor and said handle comprising separate vibration reducing devices between the hammer motor and each of said handle grips respectively and each comprising relatively rotatable parts, one connected to the motor and the other to a handle grip, and a rubber torsion sleeve bonded in shear to adjacent faces of said relatively rotatable parts.

5. In a rock drill, a hammer motor, a supporting handle therefor having handle grips mounted for independent movement, and vibration reducing means between said hammer motor and said handle comprising separate vibration reducing devices between the hammer motor and each of said handle grips respectively, each comprising an arm by which the grip portion is carried, relatively rotatable parts, one connected to said arm and the other to said motor, and a rubber torsion sleeve bonded in shear to adjacent surfaces of said relatively rotatable parts for yieldingly connecting said arm to the hammer motor.

6. In a rock drill, a hammer motor having a rear head, supporting means therefor, and vibration reducing means between said hammer motor and said supporting means comprising relatively rotatable parts, one connected to said hammer motor head and the other to said supporting means, and a resilient rubber mass bonded in torsional shear between adjacent surfaces of said relatively rotatable parts, thereby eliminating metal-to-metal contact between said motor head and said supporting means.

'7. In a rock drill, a hammer motor, and supporting means therefor including lateral projections on the hammer motor, handle arms having grip portions, and means including rubber torsion sleeves, each arranged between a handle f arm and a lateral projection, for yieldingly connecting the handle arms and lateral projections.

8. In a rock drill, a hammer motor having a back head, said head `having a boss perforated by an opening extending transversely of the drill, supporting means for the hammer motor including a bolt arranged in the opening in the head boss and having projecting ends, a sleeve carried on each end of said bolt and secured to the back head against rotative movement with respect to the bolt, handle arms each having a handle grip, outer sleeves secured within the hub of each handle arm, and rubber torsion sleeves arranged between the inner and outer sleeves and permanently bonded thereto as by vulcanizing.

9. In a rock drill, a hammer motor, a supporting handle therefor, and vibration reducing means between said handle and said hammer motor comprising a handle arm, relatively rotatable parts, one connected to said arm and the other to a part of said hammer motor, and a rubber torsion sleeve bonded in shear between adjacent surfaces of said relatively rotatable parts for connecting the handle arm to the hammer motor, said handle arm acting on said torsion sleeve with a lever action.

10. In a rock drill, a hammer motor, a Support therefor, and vibration reducing means between said support and said hammer motor comprising a lever arm, relatively rotatable parts, one connected to said arm and the other to a part of said hammer mo-tor, and a rubber torsion spring bonded in shear to said relatively rotatable parts between said lever arm and the hammer motor for yieldingly connecting the support to the hammer motor.

l1. In a rock drill, a hammer motor, and manual supporting means therefor including relatively movable handle elements mounted for mutually independent movement and each having a grip portion, and separate vibration reducing means between said handle elements respectively and the hammer motor, one vibration reducing means individual to each handle element, said vibration reducing means upon yielding thereof permitting said independent movement of said handle elements.

12. In a rock drill,` a hammer motor, a handle supporting means therefor comprising handle grips mounted for mutually independent movement, lever arms carrying said grips respectively, and separate vibration reducing means between said lever arms respectively and the hammer motor, one vibration reducing means individual to each lever arm and said vibration reducing means upon yielding thereof permitting said independent movement of said handle grips.

13. In a rock drill, a hammer motor, a handle supporting means therefor including handle grips mounted for independent movement, lever arms carrying said handle grips respectively, and means between said lever arms respectively and the drill hammer motor for yieldingly connecting said supporting means to the hammer motor,

said connecting means each including relatively rotatable parts, one part connected to a lever arm and the other to said hammer motor, and a rubber torsion sleeve bonded in shear between said relatively rotatable parts.

14. In an impact tool, an impact motor, handle grips for supporting the motor and mounted for mutually independent movement, and separate vibration reducing means between said handle grips respectively and said motor, one vibration reducing means individual to each handle grip, and said vibration reducing means upon yielding thereof permitting said independent movement of said handle grips.

15. In an impact tool, an impact motor, handle grips for supporting the motor and mounted for mutually independent movement, and separate vibration reducing means between the handle grips respectively and said motor and including torsion spring vibration reducing devices, one individual to each grip, said torsion spring devices upon yielding thereof permitting said independent movement of said handle grips.

WARREN NOBLE. 

